Category Archives: Cosmology

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Wormholes – those curious portals to the other side of the galaxy or universe. More formerly known as an Einstein-Rosen bridge, they theoretically join two regions of space allowing one to traverse great distances instead of moving along the fabric of space.

The illustrations below shows this very well. Traveling from A to B in the conventional sense will get you there in time…

Traveling from planet A to planet B via flat space.

But, fold space by using a wormhole and you now have a much shorter path to cross to go from A to B.

Traveling from A to B via a wormhole is quicker.

The new wallpaper shows the mouth of an active wormhole from the point of view of a gas giant and its habitable moon in a nearby solar system.

Astronomers, astrophysicists and cosmologists have a very difficult and frustrating life. They can’t touch the star, exoplanet, galaxy, nebula or other celestial object they are studying, nor can they send a probe as a surrogate to take a sample or direct measurement (aside from the few lucky planetary scientists who’ve had missions within our solar system). The topics of their interests lie at distances most people can’t even comprehend. They are restricted to study their subjects with light—infrared, visible, ultraviolet, x-rays, gamma rays and radio waves—that the objects emit or reflect light from another source.

So how do they study these distant objects? They take pictures in light that ranges across the spectrum, and they gather the spectra of these objects. The spectra consist of the light emitted and/or reflected from the objects, broken down it into its constituent parts which indicates what elements are absorbing or emitting the light energy.

Absorption line spectra

They then apply statistical analysis to the reams of data they’ve collected to try to understand and unlock the secrets of the cosmos. These scientists also create clever experiments and conduct observational surveys of the cosmos to provide them with data they can use to further develop their theories. And, they create models. They build computer models to test their theories and see if their models replicate or even come close to matching what they can see in the heavens above. These models are used to predict everything from stellar evolution, planetary atmospheres and black holes to galactic structures and clusters to name a few. There are those that aspire to reach even further. They want to model the evolution of the Universe from the dawn of the big bang to the present day.

A team lead by Mark Vogelsberger (MIT/Harvard-Smithsonian Center for Astrophysics) have done just that. They have developed a sophisticated model of a piece of the Universe (a cube about 326 million light-years (ly) on a side) that incorporates dark matter, as well as normal visible matter. The model, called Illustris, shows the evolution of the Universe from about 12 million years after the big bang to present day, and it maps out the cosmic webs of dark matter, along which normal visible matter collects. The amazing thing about this model is that they can zoom into it and display structures as small as galaxies like our Milky Way galaxy, which look like they could have been photographed by the Hubble telescope! These simulated galaxies exhibit similar chemistries to the galaxies we study today.

The team worked for over five years to develop this model, which incorporates over 12 billion 3D pixels to describe the sample of the Universe. If one were to try to run this simulation on a desktop computer, it would take over 2000 years to finish the calculations. Fortunately, the supercomputers used generated the simulation in 3 months of computer time. The end result contained over 41,000 galaxies embedded in the cosmic web of dark matter and visible matter.

Below is an amazing comparison of the Hubble eXtreme Deep Field image on the left and on the right side, an equivalent image produced by Illustris.

Hubble Extreme Deep Field on the left and Illustris’ simulation on the right! Credit: “Illustris Collaboration” / “Illustris Simulation”

The discovery of an unusually massive neutron star with a white dwarf companion was revealed in a paper published by John Antoniadis, a PhD student at the Max Planck Institute for Radio Astronomy and others on the international team this past April. Using radio telescopes from observatories around the planet to identify and study the neutron star, and the European Southern Observatory’s (ESO) Very Large Telescope (VLT) with its FORS2 spectrograph located at the Cerro Paranal observatory in Chili, to study the white dwarf star, the astronomers have discovered the most massive neutron star found to date. Labeled as PSR J0348+0432, the neutron star weighs in at twice the mass of the Sun.

White dwarf star orbiting a pulsar, a neutron star beaming radio frequency energy, generating gravity waves as they revolve about a common center. Image courtesy of ESO

So what? One might ask.

Well, what’s remarkable is that this mass exits in a sphere only 12.4 miles (20 km) in diameter. This means that the density of the material inside this defunct star is on the order of 1 billion tons per cubic centimeter—the size of a sugar cube! The force of gravity on the surface of the star is 300 billion times stronger than what we experience here on Earth.

This super dense ball is rotating 25 times per second and has a white dwarf companion star with a mass 0.17 that of our Sun and a diameter of 56,000 miles (90,000 km) orbiting it every 2.5 hours. This neutron star is also a pulsar. It sends a highly directional beam of radio frequency energy out into the cosmos and provided the pulsating beacon that we detected to locate this unique stellar system.

This super massive star along with it’s companion provides a wonderful natural laboratory for Earth based astronomers to study Albert Einstein’s General Theory of Relativity, which describes how space is curved by mass and energy and we observe in part as gravity. Studying this high intensity gravitational system may help us better understand gravity waves, predicted by Einstein’s theory, and explore the realm where general relativity and quantum mechanics may meet.

The team of astronomers have already measured a reduction in the orbital period of 8 millionths of a second per year due to energy being radiated from the system by gravity waves, as predicted by general relativity. Although gravity waves have been inferred by this and other binary systems, they have yet to be detected by the Laser Interferometer Gravitational Wave Observatories—LIGO—facilities on Earth.

But, wait! A sugar cube size piece of neutron star stuff that weighs 1 billion tons? How do you wrap your head around that piece of information? How do you compare that to everything you touch in your day-to-day routine? Let’s see what a billion tons of stuff might look like.

A good, massive object that most people have a concept of might be the African bull elephant.

Weighing in at about six tons on average, ten feet high by twenty feet long and eight feet wide, we would need only 167 million bull elephants to equal one cubic centimeter of neutron star material. That’s a lot of elephants!

To get a better perspective on how large this number of elephants is, consider if you packed these pachyderms side by side, front to back, you would cover an area of 26.7 billion square feet. (Whoops! We’re back to billions again. Better to convert that to square miles/kilometers.) That’s 956.5 square miles (2477 sq km); equivalent to a square with sides 30.93 miles (49.8 km) long. You could comfortably park them all in the tiny country of Luxemburg, which has an area of 998 square miles (2586 sq km), with a little room to spare.

How about something bigger, even more iconic, like the Empire State Building (ESB). Standing 1,454 ft (443.2 m) high, it has an estimated weight of 365,000 tons. We would need only 2740 ESBs to offset a balance with 1 sugar cube-size piece of neutron star stuff on it. That’s at least a number we can begin to have an intuitive sense for.

So how much area would 2740 ESBs cover? With a foot print of 79,288 ft2 (7240 m2 ) or .003 square miles (.007 square km), our collection of buildings would cover 7.8 square miles (20.3 sq km) – about 1/3 of the island of Manhattan, which has an area of 22.96 square miles (59.5 sq km). It’s a bit hard to imagine a third of Manhattan covered in Empire State Buildings. But, we can reduce the number and get a better handle on a billion tons.

Let’s take our Empire State Building and make it completely out of gold, all 37 million cubic feet (1.04 million cubic meters) of it. With gold weighing 1204 pounds per cubic foot, the solid gold building would weigh 44.5 billion pounds or 22.3 million tons. Now all we would need is 45 of these precious metal buildings to reach 1 billion tons.

This gilded collection would cover about 23 city blocks or an area from where the ESB is now to Times Square, assuming two buildings per block. Try to imagine this the next time you fly to New York City: the core of downtown Manhattan populated with 45 gleaming, solid gold Empire State Buildings and all that is equivalent to 1 cubic centimeter—one sugar cube-size of neutron star stuff.

Hopefully this helped you get a little better feel for what a billion tons might be. It’s helpful to do these simple calculations and comparisons and try to put into perspective or get a better grasp on some of the enormous numbers that come out of the study of this amazing Universe we live in.

When considering the cosmos and all the numbers we produce to describe it, I cannot help but feel that all we hold dear on this tiny blue planet, floating through the vastness of space, is insignificant when compared to what we are immersed in. Yet, we are sentient beings, and curious about the Universe we live in and that makes us very significant, because for all we know now, we are the only creatures in this entire cosmos that are looking up and asking these big questions.

The blue streak in the above image is the dwarf galaxy NGC 2366. It is about 10 million lightyears distant and located in the constellation Camelopardalis (the Giraffe), which is visible in the northern hemisphere. Barely visible to the bottom right of the blue smudge is a bright spot, which is an active star-forming nebula, NGC 2363 contained within the dwarf galaxy. In the image below you can see the nebula shining from the light of the hot blue stars that are forming in the upper right part of the galaxy.

Zooming in on the nebula in another Hubble image below, one can see the collection of bright stars embedded in the nebula. Of particular note is the very bright star that appears at the tip of the “hook” of the nebula. This massive star is known as a Luminous Blue Variable (LBV), which is about 30 to 60 times as massive as the Sun. This is a very rare type of variable and very unstable. The image captured the star during an erupting phase. Another, more famous star of this type is the giant, Eta Carinae, which is anticipated to turn into a supernova in the near future (astronomically speaking).

When you look closely at the image of NGC 2366 you will see many “nebulous” regions within it. They are actually very distant galaxies that are visible through the veil of the dwarf galaxy. I’ve highlighted some of the more prominent galaxies that can be found in the image below.

Did you know that every time you use your GPS to guide you to your destination you are applying one of the most profound ideas put forth in the twentieth century—the idea of the space-time continuum?

Albert Einstein proffered the idea in 1915 with his new theory of general relativity. He theorized that space and time are not independent, isolated entities, but merge into one element or “fabric” called space-time. The general theory addresses gravity and acceleration and shows in part that one can not distinguish between being in a gravitational field or under constant acceleration. But, it goes much deeper, as we shall see.

One can see how space and time are intimately related when you consider how the Global Positioning System works. Your location is determined by your GPS device when it receives a signal from at least 4 GPS satellites in orbit. By comparing these satellite signals to a reference signal in your GPS it can calculate the time-lag between them and thereby your distance from the satellites. By using multiple satellites your location can be accurately determined. Precision clocks on board the satellites are required to generate the satellite’s signal. These clocks will drift because of two relativistic effects that affect them: the speed they are traveling at—14,000 km/hr (8,424 mph)—and the distance from the Earth—about 26,600 km (15,960 miles).

Note that if we used only Newtonian mechanics to design the GPS system it would not work. We need to incorporate both of Einstein’s theories—special and general relativity if we are to eliminate these errors. (Newtonian mechanics are still very important and useful in determining orbital parameters of spacecraft and the planets—except for Mercury, but that’s another blog topic!)

First, let’s look at the Special Theory of Relativity, since most people are familiar with its basic premise that the closer you travel to the speed of light, the slower time passes. (Remember the twins paradox?) For the satellite in orbit moving at a high rate of speed, its clock will run slower than a corresponding clock on the surface of the Earth.

Now let’s consider the General Theory of Relativity. If a clock is in a gravitational field it will run slower the closer it is to the source of the gravity field—i.e.: closer to the surface of the Earth. The further the clock is from the source of the field, the weaker the field is—i.e.: the higher your altitude above Earth’s surface, the faster the clock will run. (The field falls off as one over the distance-squared.)

The effect on the satellite’s clock due to the gravitational field is almost six times that of the effect due to its speed. The combination of these two relativistic effects would cause your GPS to accumulate an error, which is on the order of 6 miles or 10 km per day!

This application of Einstein’s two theories shows how time and space are tied together in a way that our day-to-day life experiences would never reveal. Our internal biological clocks are being affected by the speed at which we travel and when we move through a gravitational field. So it’s not just covering a distance when you travel from point A to B, but moving through time as your biological clock changes as your speed changes and you move through a gravitational gradient. These effects are very small at the speeds we travel and the typical change in altitude we might experience. They are on the order of nano-seconds (billionths of a second)—small but real.

The center of our galaxy is a very busy place, and it has been under close scrutiny by astronomers since 1992. A team of astronomers have been watching our galactic core, peering through the veil of dust that shrouds the core using infrared eyes via the European Southern Observatory’s New Technology Telescope and the Very Large Telescope. What they’ve seen shows a group of stars doing a mesmerizing dance around an object that we can not see, but has a definite influence on their orbits. The following video from ESO gives a great introduction to this amazing phenomena.

A black hole? Like the saying goes – “If it walks like a duck, quacks like a duck and looks like a duck, it’s probably a duck!” The motion of these stars and other information gathered over the years indicates that there should be an object at the center of our galaxy with a mass equivalent to about 4 million Suns. Based on the latest theories, this should be a black hole.

Recently, Dr. Reinhard Genzel of the Max-Planck Institute and his team have discovered a cloud of dust and gas that appears to be heading for a close encounter with this object dominating our galactic center. The dust cloud, which is about three times as massive as the Earth, has doubled its speed over the last seven years, not something an object can do unless it has its own propulsion system or it is in a substantial gravity well – i.e. in the grip of a black hole. Astronomers predict that the cloud will pass by the black hole at a distance of about 40 billion kilometers – equivalent to about ten times the distance between the Sun and Neptune. The following video shows the time-lapse motion of the cloud as well as stars at the core.

Although the cloud is being ravaged by the black hole now, in 2013 it should be at its closest to the black hole and be ripped apart. This encounter should be indicated by a brightening of this region, especially in X-ray portion of the spectrum, as the dust and gas particles are heated to millions of degrees as they collide with each other while spiraling down to the event horizon of the black hole and beyond.

The following video shows a simulation of the cloud in red/yellow as it approaches the black hole. The time frame is from the year 2000 to 2043.

This will be a great opportunity to see a black hole feeding, as well as testing Einstein’s General Theory of Relativity as it applies to black holes. We can look forward to some celestial fireworks in 2013!

November 9 was the anniversary of Carl Sagan’s birth. He would have been 77 years old.

Carl Sagan has gently ushered millions of people across this blue planet into the wonders of the cosmos. One of his most poignant observations on this Universe we live in is his comment on Earth – “The Pale Blue Dot.”

Take five minutes and watch this video. All that we hold dear, all that has any meaning to us, everything that has ever been to bring us to today has occurred on this planet. This tiny speck in the vast Universe. The military rulers, presidents, kings and queens, gang leaders, politicians, drug dealers, criminals that have left death, destruction and despair in their wake, as they struggle for dominance in their small corner of this dot don’t appreciate their insignificance in the grand scheme of things.

We need to understand that we are one people – one planet. It doesn’t matter what color we are, what language we speak, what nationality or religion we are, we are all humans and we exist only in one place in this vast cosmos. We need to work together to survive, which means compromise and sacrifice from everyone. If we fight for dominance, we surely are destined to all fail.

Think about IT and DO….

Thank you, Carl, for your perspective on this world we all live on. Let’s hope we can all learn to appreciate what we have before we lose it.

The Hubble Space Telescope has taken a fascinating image of a planetary nebula known as the Necklace Nebula.

Planetary nebula are the remains of a star like our Sun as it goes through the final stages of its life expanding and blowing off its outer layers. The bright blobs embedded in the nebula are areas of gas that are energized by ultraviolet light from the star at the center. The blue-green color of the nebula reflects the hydrogen and oxygen present, with red indicating nitrogen. The Necklace Nebula lies about 15,000 light years from us and is located in the constellation Sagitta.

It’s interesting to compare this planetary nebula with the remains of the supernova 1987a:

Another piece of cosmic jewelry, but one made from a very different process and from a star that was much larger than our Sun. The supernova is the foundry that produces all the heavy metals we have today, from the iron in the hemoglobin of your red blood cells to the gold and silver in the jewelry you may be wearing right now.

Both of these nebulae are still evolving, and as time passes they will continue to evolve into new shapes, and eventually (10s to 100s of thousands of years) they will fade from view. But, their remains will fuel the next generation of stars and planets in the cosmos.

Kepler has opened up the Universe for us with evidence that there are many more planets orbiting stars than we previously thought. The consequences of this is that the potential for life beyond Earth has grown exponentially. Recent news from a team of astronomers lead by Takahiro Sumi from Osaka University in Japan and published in the journal Naturehas revealed that there may be as many as 400 billion planets roaming the Milky Way Galaxy, free from their parent stars.

This discovery was made by using a technique called gravitational lensing or microlensing in this particular case. According to Einstein’s General Theory of Relativity, the gravitational field of a massive object will bend light that passes through it. This technique has been used to view distant galaxies that are behind an intervening large cluster of galaxies, which magnify and distort the image of the more distant objects.

In the case of gravitational microlensing, the intervening objects are these rogue planets and the distant objects are stars. The alignment of the star, planet and Earth is almost perfect, such that when the planet passes in front of the star its gravitational field causes the star to brighten and dim in a predictable fashion. This is a brief event and will not repeat itself.

These objects are similar in mass to Jupiter. And, if they are truly planets or possibly brown dwarf stars (small stars that generate heat but are too small to trigger the fusion process to burn brightly), they may have been ejected from their solar system of birth through the normal dynamics that force a solar system into a stable state. Interestingly, this challenges the definition of planet, which was decided upon by the International Astronomical Union (IAU) and led to Pluto’s demotion to dwarf planet, but that is a a discussion for another blog.

The objects detected are fairly massive, which begs the question: What about smaller Earth-like planets? Can we see them and how many of them are there out there? As usually happens in the world of astronomy, discoveries bring more questions than they answer.

The discovery of these objects challenges the current theories of planetary evolution and possibilities for life in the Universe. More research in this area will be conducted when NASA’s Wide-Field Infrared Survey Telescope (WFIRST) is launched, allowing for the faster blips of light to be detected, indicative of Earth-mass type objects.

Kepler’s been in the news lately, revealing some of its latest discoveries. At the time I’m writing this, Kepler has logged 1235 potential planets and 1879 eclipsing binary stars. Of the 1235 planetary candidates, 15 have been confirmed to be real planets. That may seem like a very small number, but it takes time to confirm these candidates with ground/space based telescopes. The number is sure to rise.

As I was looking at the Kepler site, it struck me as to how small Kepler’s view is of the entire sky. It covers an area of about 105 square degrees. Now that’s a pretty large area when you consider that our full Moon spans about a half a degree, and has an area of about .2 square degrees. But, if you think about it from the point of view of the entire visible sky, which covers 41,253 square degrees (encompassing both the northern and southern hemispheres), Kepler is only sampling 0.25% of the sky! If Kepler’s sample of our galaxy is typical of the entire galaxy, then we could expect a minimum of about 500,000 planets in the galaxy with equivalent short period orbits.

Remember that these planets pass between their stars and Kepler, so any star systems in which the planets rotate in a plane almost perpendicular to Kepler’s view would not be recorded. So, this rough number is even a smaller percentage of the potential total number of planets out there. Oh, and don’t forget about the moons that may orbit these planets (and others yet discovered) and could have atmospheres and environments conducive for life to form.

Out of these potential candidates, 68 are known to be Earth-sized and 288 fit the category of “super-earth”-size ­-­ 2-5 times the size of the Earth. These are all rocky-type planets, verses the gas giants like Jupiter. Some of these are also in or near the habitable zones of the stars they orbit. This is a region where temperatures on the planets would allow water to exist in a liquid state, essential for most life as we know it on Earth.

Almost two years of Kepler’s 3.5 year mission has passed, and it has documented 1235 planetary candidates. This means that these potential planets have passed in front of their parent stars at least 4 times in this two year period to provide reliable data to confirm that it’s a planet. In the next one-and-a-half years, more planets will be documented as they pass in front of their stars causing the star’s light to dim and allowing Kepler to record another transit. The longer Kepler looks at a star, the more planets it will see, because they are further from the star and have longer orbital periods.

If Kepler were looking at our Sun, it would have already documented Mercury, because Mercury orbits the Sun every 88 days. (Actually it would have to be a much larger version of Mercury to be seen by Kepler.) Venus would also have been identified, with its orbital period of 224 days, three transits could have been recorded in two years. Earth could also be a likely candidate, but unconfirmed with two possible transits in the two year observation period. But, Kepler wouldn’t have anything more than possibly one transit for Mars and/or the other planets beyond it during this time period. With Jupiter’s orbital period of almost12 years, it would take 48 years for Kepler to gather enough data to confirm its existence.

The cosmos is teaming with planets, I have no doubt. I also think that the cosmos is teaming with life, in some shape or form. Our own experience with extremophiles here on Earth should be a good indication that life will find a way. How advanced that life is, is open to debate. Time will tell.

If you would like to participate in identifying potential planets from the data that Kepler has produced, take a look at the site: Planet Hunters. At the site you will go through some training and then will be able to identify transits that may indicate a planet passing in front of a star. A nice way to be able to participate in a profession astronomy project.